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From: B. Harris)
Subject: Re: The Ringer's solution and my father's death
Date: 24 Apr 1998 06:20:44 GMT

In <6hmhrr$448$> (Greg McArthur)

>Just to add some pseudo facts to this dicsussion, the content of
>Ringers solution is:  (and this is off the top of my head from 20
>years ago in school)...
>sodium chloride, potassium chloride, and calcium chloride for ionic
>balance; manitol to control osmotic pressure;
>phosphate buffer and HCl to adjust pH.
>Normal Saline is just 0.9% NaCl solution.
>Neither provide any nurishment.
>Greg McArthur
>Sr. Engineer
>Merit Medical Systems, Inc.

   These days, BTW, the hot stuff in fluid resuscitation crystaloids is
hypertonic saline, which has an osmotic kick which is useful in opening
capillaries and decreasing swelling which results from ischemia.  Lot
os papers on this, generally comparing it to Ringer's, on medline.

                                        Steve Harris, M.D.

From: B. Harris)
Subject: Re: Dehydration/Rehydration IV fluids???
Date: 16 Mar 1999 06:05:18 GMT

In <> writes:

>Dear Group,
>I know I'm showing my dummy strips, but for the great educators out
>there, help me understand this.
>What fluids do you use?
>Are there any quick little rules of thumb to know when to hang D5W1/5NS
> vs. NSS?
>When to hang isotonic?
>When to hang hypotonic?
>When to hang hypertonic?
>When not to hang Lactated Ringers?
>I read the rationales, think about them, they make sense, then they slip
>my mind again. Any little jingles out there?
>Thanks, Vera

   Never hang lactated Ringer's.  It's a waste of money.  Of course,
you don't get to make that decision.

   Think of D5W as like drinking-water-- the icewater at your patient's
bedside, for example.  When the glucose is metabolized out, that's
what's left.  It's pretty safe for everybody except the rare person
with very low sodium levels due to some disease like SIADH or a
psychiatric problem that makes them drink too much.

   As a first pass, you can just figure that in a patient with no
history of congestive heart failure, with even half-working kidneys
(they are making urine in normal amounts, and their creatinine levels
are below 2), who has normal sodium levels and isn't volume depleted
(orthostatic), it really doesn't matter much how much NS goes in with
the D5W.  You can hang D5W/NS, or D5W/0.2 NS and it's all the same.
The average person retains salt very well, so D5W alone (or with some
potassium-- which everybody needs more of than sodium, so long as their
kidneys are working) is fine for a day or two.  People who go beyond
that usually need TPN anyway.  Sometimes a solution of D5W/ with a .2
or .25 NS, and some potassium, is used for maintainence in normal
people, but it's really more salt than the average person needs.  But
then so is a Big Mac.   The only people who get in trouble this way are
folks who easily go into congestive heart failure.  They get D5W with
potassium only, as a rule.

   People who are badly dehydrated often get NS with potassium until no
longer orthostatic, and until their pulse rate normalizes.  It's as
good as anything at reversing this.  Sometimes people who are
dehydrated with very high sodium levels get D5W with some fraction of
NS to try to bring sodium levels slowly down, but this is done
according to a tricky formula which often doesn't work very well.
Lots of plain NS often just the job just as well.    And you can give
just about anybody 300 cc of plain NS over 20 minutes to see what
happens, if you have any question about whether or not they need more
volume (salt and water).  If pulse comes down and blood pressure up,
you know you're headed in the right direction.

    There is much in the above that isn't covered (whole texts are
written about this).  But that's a first pass.

                                          Steve Harris, M.D.

From: B. Harris)
Subject: Re: Dehydration/Rehydration IV fluids???
Date: 16 Mar 1999 08:00:20 GMT

In <7ckjtd$> "Jim Fuchs" <> writes:

>As for hypertonic solutions (like hypertonic saline).....these are used
>rarely, and with great care. I can only think of one situation....that of
>symptomatic hyponatremia. Maybe there are others out there who can think
>of other appropriate uses.

   Not on the wards, but you're going to see small volumes (like 4
cc/kg) of 7% saline used more and more for field resuscitation from
hemorrhagic shock.  None of the plasma expanders stay in the
intravascular space anyway, and there's something kind of magic about
hypertonic saline, and hypertonicity in general, in ischemia.  It
shrinks swollen RBCs and capillary endothelium, which have blown up
osmotically due to ischemic ATPase pump failure.  And that restores
flow and rheological properties without the fluid expansion which can
sometimes just bring on more bleeding, before trauma loss can be
controlled.  And weensy bags of hypertonic saline are small and
portable and cheap and and don't need refrigeration.  The army,
naturally, is intrigued.  As are all those third world countries, where
it takes a lot more than the golden hour to get trauma victims to
surgery, and there isn't any money for fancy paramedic training or for
keeping complicated blood bank products field-usable.

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